The present invention relates to an industrial vehicle such as a lift vehicle and more particularly to a vehicle speed responsive load carrier of a lift vehicle.
A vehicle speed responsive load carrier is known which comprises a push-pull mechanism with a face plate. The push-pull mechanism includes a hydraulic actuator which, under the control of a control unit, displaces the face plate longitudinally in response to a ground speed of the vehicle.
One such load carrier is disclosed in JP-A 57-195098. In this known device, there are provided two sensors, one for measuring a velocity at which the face plate displaces relative to the vehicle body, the other for measuring a ground velocity at which the vehicle displaces, and an electro-hydraulic module is disposed in a hydraulic circuit to regulate fluid supply to the hydraulic actuator in response to the output signals of the sensors. The sensors and electro-hydraulic module are expensive. The whole system is composed of an electronic control part and a hydraulic control part which have different response speeds to external disturbances so that it is difficult to suppress occurrence of hunting and overshooting phenomena.
One object of the present invention is to provide a vehicle speed responsive load carrier which is not provided with such a complicated electro-hydraulic module as used in the prior art as mentioned above.